Conservative Leader Stephen Harper addresses a crowd at the College of Applied Arts and Technology at a campaign stop in Sault Ste. Marie, Ont., on April 25, 2011. (Adrian Wyld/The Canadian Press/Adrian Wyld/The Canadian Press)

Conservative Leader Stephen Harper addresses a crowd at the College of Applied Arts and Technology at a campaign stop in Sault Ste. Marie, Ont., on April 25, 2011.(Adrian Wyld/The Canadian Press/Adrian Wyld/The Canadian Press)

Ridings to watch

Battleground Ontario: How the final campaign week is shaping up
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The dynamic: The battle for the 'burbs is largely a Liberal vs. Conservative affair in the 905 area code, the NDP's Hamilton base being the exception. Midway through the campaign, polls showed the Grits and Tories essentially tied in Ontario. Now the Tories are clearly in front and expanding their lead. As that lead grows, more of these ridings can be expected to switch from red to blue. These suburban ridings will also test the appeal of the Conservative outreach to ethnic communities, particularly in Brampton and Mississauga.

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The dynamic: Voters in Kitchener and London must be wondering what they did to merit all this attention. While most Southwestern Ontario incumbents are considered safe, two of Kitchener's three Conservative ridings could fall back to the Liberals, and tight races are expected in London's three ridings, particularly London West. May 2 will also mark the latest development in the saga of Helena Guergis, who is expected to put up a good fight as an "independent conservative" in Simcoe-Grey.

City of Toronto

Total ridings: 22

Number of ridings that could swing: four

The dynamic: This is the base of the Liberal Party, yet it's not as solid as it once was. Conservatives are chipping away from the suburban edges, while NDP Leader Jack Layton and Olivia Chow - his wife and caucus mate - are trying to expand their party's appeal in the city's core. Ms. Chow always faces a tough fight in Trinity-Spadina, while the NDP's Peggy Nash will try to win back Parkdale-High Park, which she lost to Liberal Gerard Kennedy in 2008. The Conservatives are expected to be competitive against Liberals Joe Volpe in Eglinton-Lawrence and Ken Dryden in York Centre.

Eastern Ontario

Total ridings: 17

Number of ridings that could swing: three

The dynamic: Uniting the right turned Eastern Ontario into a reliable source of seats for the Conservatives. Kingston and the Islands is the most unpredictable riding, given that Liberal incumbent and former House of Commons Speaker Peter Milliken is not running again. The Liberals are expected to challenge the Conservatives in Ottawa-Orleans, while Liberal-turned-independent Hec Clouthier is earning buzz with his attempt to defeat Conservative Cheryl Gallant in Renfrew-Nipissing-Pembroke. Long-shot bids for the Liberals would be in Glengarry-Prescott-Russell and Ottawa West-Nepean, currently held by Conservative House Leader John Baird.

Northern Ontario

Total ridings: 10

Number of ridings that could swing: four

The dynamic: May 2 will determine whether Conservative efforts to target rural ridings over the long-gun registry paid off. Four ridings are considered close races, including three that are held by the NDP. The fourth, Kenora, saw the Conservatives narrowly defeat the Liberals last time.

All three national parties are competitive in Northwestern Ontario, making Kenora, Sault Ste. Marie and Thunder-Bay-Superior North races to watch on election night. Sudbury is largely a battle between NDP incumbent Glen Thibeault and the Liberals, who held the riding before the 2008 election.